Very narrow band excimer or molecular fluorine laser

Abstract

An excimer or molecular fluorine laser system generates a laser output bandwidth of less than 0.6 pm, and preferably 0.5-0.4 pm or less. The laser resonator has a line-narrowing unit preferably including a grating, and preferably also a beam expander, and may include one or more etalons or other interferometric devices. The grating may be preferably a blazed grating having a blaze angle greater than 76°, and is preferably around 80°. The grating structure is preferably defined by the surface of the grating substrate. The substrate is preferably aluminum. The system may further include an amplifier for increasing the energy of the sub-0.6 nm output beam.

What is claimed is:  
     
         1 . A method of forming a diffraction grating in the surface of a substrate, said method comprising the steps: 
 generating an ion beam;    patterning said ion beam;    impinging said patterned beam onto said surface to thereby form said grating therein.    
     
     
         2 . A method of  claim 1 , wherein said patterning comprises passing said beam through an attenuator having a structure according to the structure of said grating.  
     
     
         3 . A method of  claim 2 , wherein said attenuator is substantially made of epoxy.  
     
     
         4 . A method of forming a diffraction grating in the surface of a substrate, said method comprising the steps: 
 providing an ion beam;    attenuating said ion beam according to the structure of said diffraction grating;    irradiating said surface with said attenuated beam;    wherein said attenuated ion beam forms said grating in said surface.    
     
     
         5 . An excimer or molecular fluorine laser, comprising: 
 an oscillator for generating a pulsed sub-0.6 nm, sub-250 nm laser beam, including: 
 a laser tube including a discharge chamber filled with a laser gas mixture at least including molecular fluorine and a buffer gas;  
 a plurality of electrodes in the discharge chamber connected to a pulsed discharge circuit for energizing the gas mixture;  
 a resonator surrounding the gas mixture for generating a pulsed sub-250 nm laser beam; and  
 a line-narrowing unit for narrowing the bandwidth of said laser, said line-narrowing unit including a grating and narrowing said bandwidth to less than 0.6 pm, and  
   an amplifier for increasing an energy of the pulsed sub-0.6 pm, sub-250 nm laser beam, including 
 a laser tube including a discharge chamber filled with a laser gas mixture at least including molecular fluorine and a buffer gas;  
 a plurality of electrodes in the discharge chamber connected to a pulsed discharge circuit for energizing the gas mixture at times when pulses of the sub-250 nm laser beam generated by the oscillator are present within the discharge chamber; and  
 a resonator surrounding the gas mixture for generating a laser beam.  
   
     
     
         6 . The laser of  claim 5 , wherein said bandwidth is less than 0.5 pm.  
     
     
         7 . The laser of  claim 5 , wherein said bandwidth is less than 0.4 pm.  
     
     
         8 . The laser of  claim 5 , wherein said grating has a blaze angle of at least 78°.  
     
     
         9 . The laser of  claim 5 , wherein said grating has a blaze angle between 78° and 82°.  
     
     
         10 . The laser of  claim 5 , wherein said grating has a blaze angle greater than 80°.  
     
     
         11 . The laser of  claim 5 , wherein said grating has a coating comprising a reflective dielectric material.  
     
     
         12 . The grating of  claim 5 , wherein said grating has at least 10,000 grooves per centimeter.